The present invention relates to both a method and an apparatus for compensating for the image rotation produced by relative movement of the various parts of an articulated optical system which consists of members having lenses for optical focusing as well as articulations with mirrors or prisms for deflecting the ray path.
Articulated optical systems are used, for instance, in conjunction with operation microscopes and endoscopes in order to attach to such microscopes or endoscopes devices for simultaneous observation and/or documentation, e.g. still cameras, motion picture cameras, or television cameras. In this case it is desirable to relieve the operation microscope or endoscope from all the accessories so that it can be moved as easily as possible in all directions. The simultaneous- observation and documentation devices are therefore fixed on a special supporting arm and are connected flexibly with the operation microscope or endoscope. For this purpose, there are used articulated optical systems which consist of members with lenses for optical focusing which are connected by articulations in which mirrors or prisms deflect the ray path. Various members are able to move relative to each other telescopically or rotationally, or both. The disadvantage of known articulated optical systems resides in the fact that the displacement of the operation microscope or endoscope and the change in the articulations caused thereby causes the image to be rotated. This rotation of the image can be compensated by suitable optical elements, but the known devices, in which this must be carried out by hand, require an amount of handling which is excessive in practice.
In West German unexamined patent application (offenlegungsschrift) 27 54 614 there is described an articulated optical system in which the image rotation is automatically compensated by connecting the articulations with each other by mechanical transmissions, and in each member there is provided an additional reflection prism which is turnable by gears around its longitudinal axis. Such an articulated lens system is very demanding in mechanical and optical respects, particularly if space for manipulation in all directions is desired for the operation microscope or endoscope and numerous articulations are thus necessary.